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Re: Removing unneeded self joins - Mailing list pgsql-hackers

From Zhihong Yu
Subject Re: Removing unneeded self joins
Date
Msg-id CALNJ-vTyL-LpvSOPZxpC63Et3LJLUAFZSfRqGEhT5Rj7_EEj7w@mail.gmail.com
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In response to Re: Removing unneeded self joins  (Zhihong Yu <zyu@yugabyte.com>)
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On Fri, Aug 26, 2022 at 3:02 PM Zhihong Yu <zyu@yugabyte.com> wrote:
Hi,
For v36-0001-Remove-self-joins.patch :

bq removes inner join of plane table to itself

plane table -> plain table

For relation_has_unique_index_ext(), it seems when extra_clauses is NULL, there is no need to compute `exprs`.

Cheers

For remove_self_joins_recurse():

+                   if (bms_num_members(relids) > join_collapse_limit)
+                       break;

The above line just comes out of the switch statement. This check should be done again between foreach and switch.
Otherwise the above check wouldn't achieve what you want.

Cheers

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